1. Field of the Invention
The object of the invention is to provide an improved hydraulically actuable jib for a loading crane.
2. Description of Related Art
Hydraulically actuable jibs for loading cranes are already known in large numbers from the state of the art. Thus, for example, EP 0 566 720 B1 of Nov. 10, 1992, discloses a multi-stage telescopic jib, in particular for a loading crane on a truck, wherein a respective hydraulic unit having a piston and a cylinder is arranged between successive telescopic arms arranged one within the other, wherein, at least in regard to the cylinder of the innermost arm, a tube projects from the cylinder end axially into the cylinder chamber, the tube, when the piston is at least partially retracted, extending into the hollow piston rod in sealed relationship with the piston, and thus sealing off the cylinder chamber with respect to the internal chamber in the hollow piston rod, wherein the internal chamber in each hollow piston rod is connected to the cylinder chamber of the next inner hydraulic unit by way of a preferably rigid line, and the internal chamber in each hollow piston rod communicates with the cylinder chamber of the same hydraulic unit when the piston is fully extended.